Is 104C too hot for a 4.9L 1994 Deville?

My 1994 4.9L runs around 101-104C in 84 deg. F weather with the A/C on just driving around. Is 104C too hot for a 4.9L? What is the normal operating range for the 4.9L? What temp does the coolant have to be for the warning light to come on? Any info would be appreciated. Thanks.

Re: Is 104C too hot for a 4.9L 1994 Deville?

Originally Posted by Twilightcall

My 1994 4.9L runs around 101-104C in 84 deg. F weather with the A/C on just driving around. Is 104C too hot for a 4.9L? What is the normal operating range for the 4.9L? What temp does the coolant have to be for the warning light to come on? Any info would be appreciated. Thanks.

Well if I knew the conversion, I'd be able to tell you. Switch the system over to standard (on the climate control panel somewhere) and see what the degrees are in Fahrenheit. It should run around 213 degrees Fahrenheit.

Re: Is 104C too hot for a 4.9L 1994 Deville?

I would say it is NOT ok. It is the cadillac politic to design a car that operate very silence because customers want a silence and smoothe car, but more than 95°C for EACH car no matter if alluminium motor or not is too hot. Belive me - I already have killed two cylinder head gaskets on two cadillacs. I have my third Eldorado equiped with an extra switch on my panel so I can start the ventilator from inside. Cadillacs are programmed to heat up to 118°C befor starting the vent. And this is too hot. It takes about 40 minutes in stop and go traffic to get those 118°C befor the sensor starts the blower. This will kill each motor !!!

Re: Is 104C too hot for a 4.9L 1994 Deville?

Originally Posted by tomtom

I would say it is NOT ok. It is the cadillac politic to design a car that operate very silence because customers want a silence and smoothe car, but more than 95°C for EACH car no matter if alluminium motor or not is too hot. Belive me - I already have killed two cylinder head gaskets on two cadillacs. I have my third Eldorado equiped with an extra switch on my panel so I can start the ventilator from inside. Cadillacs are programmed to heat up to 118°C befor starting the vent. And this is too hot. It takes about 40 minutes in stop and go traffic to get those 118°C befor the sensor starts the blower. This will kill each motor !!!

Your head gaskets blew for another reason: 213-220 degrees in drive at idle is NORMAL for these engines. Even our chief site engineer Bbob (designed Northstar and had a hand in the 4.x engines) has stated that both the 4.x engines and the Northstar engines run this warm and are fine with those temperatures.

My '87 Seville ran at the 213 degree area with nary a problem, as does my performance upgraded 4.9 liter engine. Even a friend of mine that owns a '95 STS runs this warm when in drive at idle.

When the air gets through the coolant flow, the engine will cool down from that while driving. When at a stop in drive, expect those temperatures: It is normal.

Re: Is 104C too hot for a 4.9L 1994 Deville?

Yes, I know that this high temperatur is normal for a Cadillac but nevertheless it is too hot. No Buick, no Chrysler, no Ford, no European and no Japones car have this high temperatur. My Eldo runs with 90°C when air blows through the radiator.This is ok. Stopping in drive it climbs up to 118°C as every Cadillac do and this is pretty unhealthy for the head gaskets.

Re: Is 104C too hot for a 4.9L 1994 Deville?

ok so what would you like him to do about the temperature ? is there a way we can scrub 10c off the temperature ? do not tell someone there is a problem if you do not have the fix , because your going to scare this poor guy who just wants to know if its normal ...

it appears your eldo runs exactly like my deville , tooling down the road i get down to 90c also ....so it appears to me your cooling system works exactly like mine

your talking a changeing the engine in a manner outside its desgin characteristics...which is dangerous...but if you have an idea to scrub off coolant temp in drive at idle on a hot summer day tell me ....

what is the normal temp now for cars ? cadillacs run a bit hot but not that much out of the average , which las time i checked was 190-200 degrees , not far off from the 210 we see in the cadillacs , hell i bet i can get the same 190-200 everyone else gets if i move the coolant temp sensor to another location ...the average coolant temp for a cadillac is claoser to the industary avegrage of 195 then it is to the indsustry average for danger of 240 ..

Plus remeber , we are talking about a engine with an alumium block , which in itself gets rid of heat too ....220 in a iron block car and 220 in a alum block are two diffrent things

you blew your head gaskets because the coolant wasnt changed yearly and you didnt use the GM coolant suppliment ....that is the single most important thing you can do with the iron head/aluminum block (4100/4.5/4.9 series) engines ...and its extra insurance for the nrothstars

i dont want to scare you off or offend you but i dont want you to scare twilight either ...

Re: Is 104C too hot for a 4.9L 1994 Deville?

There are two ways to keep the temperature on a 90°C level. An expensive one and a cheap one. I selected the cheap one : I installed an extra circuit on my dashboard. Everytime I have to stop in drive for longer time and the temperature exceeds 100°C I turn on the blower by hand.
The expensive way is to installe an extra thermostat ( you can get them for older English cars like Austen Healey ) that starts the blower automaticily on 95°C.

Re: Is 104C too hot for a 4.9L 1994 Deville?

Originally Posted by tomtom

There are two ways to keep the temperature on a 90°C level. An expensive one and a cheap one. I selected the cheap one : I installed an extra circuit on my dashboard. Everytime I have to stop in drive for longer time and the temperature exceeds 100°C I turn on the blower by hand.
The expensive way is to installe an extra thermostat ( you can get them for older English cars like Austen Healey ) that starts the blower automaticily on 95°C.

Where exactly do you put this extra thermostat? And how does an extra thermostat help to controll the cooling fans? Is this extra thermostat electronic as opposed to the mechanical one?

I'm totally confused with your post dude.

Now the fan override switch can be had at Jegs...But an extra thermostat?

Re: Is 104C too hot for a 4.9L 1994 Deville?

well its a thermostat for the fans , not the classic coolant thing ...

we used them when we retrofitted our airforce tow tractors from a mechaical fan to electric fans ....also bougth from jegs ...solid state units , i think the ones we had could be adjusted to a desired kickon temp ...its been years ago tho ...

i will have to agree with tomtom but its about GM in general , they seem to put off fan engagement till the last minute , our new malibu even waits too long before the fans kick on or kick on full blast ...

ill have to look into it and see if i can find those adjustable fan stats